


Fellcest Kinktober 2018

by Sin_Cognito



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell (Undertale), BDSM, BDSM discovery, Ecto-Genitalia (Undertale), Kinktober, M/M, Underfell Papyrus (Undertale), Underfell Sans (Undertale)
Language: English
Status: In-Progress
Published: 2018-09-30
Updated: 2018-10-15
Packaged: 2019-07-20 21:31:30
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 15
Words: 15,867
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16145936
Author URL: https://archiveofourown.org/users/Sin_Cognito/pseuds/Sin_Cognito
Summary: One kink a day keeps the orgasms coming as they say... or not.Join Boss and Sans as they discover BDSM culture together, trying a new kink each day.





	1. prologue

**Author's Note:**

> Ever since I've read a month to remember by arukas, I've always wanted to do a fellcest version, and even if I'm currently busy with so much stuff, I really want to give it a try. I won't be switching their roles like in a month to remember (Boss will dom and Sans will sub), but to keep the random part of the original fic, I'm letting a dice decide if they enjoy the kink or not! So we'll see what Boss and Sans like!  
> Also, I don't plan on including any other skele to the duo, so I kept Underfell Sans' name as just 'Sans', and not the usual 'Red'. So yeah, this isn't intended as kedgeup.

"SANS!"

At the sound of Boss' booming voice, Sans opened an eye, grunting from where he had been sleeping on the couch. The voice seemed to come from Boss' room, so way too far from where Sans was willing to go. So he just turned on the couch and closed his eyes again. Surely if Boss really needed him for something, he'd come get him. And if it wasn't important, then Sans might as well go back to sleep.

"SANS, DID YOU HEAR ME?" Boss tried again as he ran down the stairs, his stomping making the whole house shake. Still, Sans kept his eyes shut. If Boss thought he was sleeping, he wouldn't bother him with whatever task he had in store for Sans.

He started when he felt gentle fingers brush his cheek, and couldn't help opening one eye, taking in the form of his brother hunched over him. Boss was sat next to the couch and was looking at him with a tender smile. His gloved fingers kept caressing his face and Sans turned a bit to lean into the touch.

"Well, Good Morning, My Sleeping Fuckface. Slept Well?" Boss asked, an amused grin forming on his mouth.

"until i saw your ugly face, yeah," Sans retorted, unable to keep a smile of his own from tugging at the corner of his mouth.

"I Want To Show You Something," Boss said, standing up and placing his hands on his hips, waiting for Sans to get up and follow him.

But sans didn't really want to move. The couch was so comfy, and he knew he would have no problem going back to sleep if Boss left him there. So he closed his eyes again, letting Boss know how he felt about going with him to see whatever he wanted to show him.

"Come On," Boss insisted. "You're Going To Love It."

Hmm... That made Sans open his eyes again, curiosity winning against his desire to go back to sleep. But he was still too lazy to actually get up, and just lifted his arms toward Boss, his mouth turning into a little pout.

Boss rolled his eyelights and sighed, but still bent down and picked Sans up, who instinctively wrapped his arms around Boss' neck and his legs around the taller skeleton's middle. Boss secured him by placing his arms under Sans' body, tightening his embrace. Feeling safe in his brother's hold, Sans relaxed and let his head fall on Boss' sharp shoulder, ready to fall asleep right there. Then they went upstairs to Boss' room and he settled on the chair in front of his desk. Sans turned a bit on Boss' lap to look at all the papers on the desk, knowing full well not to actually read them, those papers containing confidential royal guard related stuff.

Boss rummaged through the papers for a while, stacking them into neat piles, and drew out one with his handwriting on it. It looked like some kind of list.

"So Lately, I've Been Thinking About How To Widen The Specter Of Activities We Can Do In Bed," Boss started, but Sans interrupted him with a snort.

"you mean, beside sleeping?"

The mere look of annoyance from Boss was enough to shut Sans up.

"So," he continued as if he hadn't heard Sans' remark, "I've Been Doing Some Research And Found Many Websites Dedicated To The Subject. I Collected A List Of Kinky Activities I Want To Try With You If You're Willing To."

Sans arched an eyebrow as Boss wiggled the paper in front of him. He took the paper and read through the list, his brow furrowing a bit at the words. Some of them he knew and some he didn't, but the overall list screamed something he found really unattractive.

"paps... those are... bdsm stuff, no?" He asked more seriously, his light tone from earlier gone.

He knew it was something Boss had always wanted to try, but he honestly wasn't a fan of the whole idea of getting hurt. He was a 1 HP monster and had to be constantly careful not to dust from a simple paper cut. So Boss suggesting doing something like this when he knew Sans wasn't into it...

"I Know, Sans. That Is Why I Only Picked The Ones That You Might Enjoy, And That Aren't Too Dangerous For You. Of Course, If You Don't Want To Do It, I Won't Force You," Boss reassured him and kissed the top of his skull.

Sans hummed in thought, eyeing the list again. It was true there were some kinks in there that he was curious about or that he wanted to try. But there were also some that he knew he would have a hard time with.

He turned to look at Boss, the look of pure patience on his face letting him know he would be respectful of his decision, whatever it would be.

Maybe...

Maybe he could try?

"okay... we can try," he said quietly.

Boss smiled and hugged him tightly, placing a kiss on the top of his skull again. "Thank You Sans! I Promise I'll Be Careful And That I'll Do Everything In My Power To Make It As Enjoyable For You As Possible!"

"but!" Sans lifted a finger. "if we're doing this, i want to do it properly. i want safewords, both word and gesture, and if i say it or do it, you have to stop completely and not ask any question."

"Of Course, Sans. And That Goes Both Ways. If I Am Uncomfortable With Anything, If I Say The Safeword, You Have To Promise You Won't Try To Get Me To Continue," Boss added.

"i thought you chose the kinks for your list? then why...?"

"I Got The Inspiration From An Existing List, So Not Every Kink Appeals To Me. Some I Chose Because I Thought You Would Enjoy Them, More Than Me. And I Don't Know, Maybe Some That I Find Hot When I Think About Them Won't Actually Be Enjoyable. That Is Why I Want To Try Different Things," Boss explained.

That made sense, Sans thought. "okay then. i promise i won't ask you to continue if you say the safeword."

"Another Thing, I Want You To Be 100% Honest With Me If I Ask You How You Feel Or If You're Hurt Or Anything. If I Find Afterward That You Kept Things From Me, I'm Going To Be Really Upset. Okay, Sans?"

The smaller skeleton looked shyly to the side, knowing he would have trouble getting rid of his tendency to omit to say the truth to his brother when he knew it would upset him. But if he wanted this experiment to work, he had to be honest with Boss. He deserved it.

"okay. i swear to tell you when i'm not feeling well," he promised as he locked his gaze with Bloss to let him know there was no deceit in the promise.

Boss looked over the list once again, smiling as he finally said, "We're Going To Have Fun."


	2. day 1: spanking

Sans was comfortably sprawled accross Boss' lap, his arms around a pillow to help him keep his balance. He was naked while Boss was only shirtless, the feel of Boss' leather pants on his bare bones soft and cool. At his lover's request, Sans had summoned an ecto butt that Boss was currently caressing lovingly, his pointy phalanges scrapping against the soft magic from time to time, making Sans almost purr.

But as good as it felt, Sans wanted more. Sure, he liked it when Boss kneaded his magic like that, but he wanted more, he wanted Boss to really _touch_  him.

"boss... more..." He whispered in a content sigh.

Boss only hummed, his hands running in circles accross the soft ecto flesh before drawing away. Sans held his breath, ready for Boss' fingers to penetrate him. He wasn't that wet yet, but surely with Boss' expert ministrations, he would soon-

*SPANK*

The loud sound, more than the feel, of Boss' hand smacking against his butt had Sans' eyes shot open. He turned in indignation toward his brother, gawking at him.

"What?" Boss laughed at Sans' baffled expression. "Today's Kink Is Spanking. What Did You Expect?"

'not this' Sans bitterly thought, knowing Boss would laugh at him again if he said it out loud. Of course, he knew what spanking meant, but he thought there was more to the kink than just... receiving a smack on the ass.

"hmpf. 'm not sure i want to do the whole month if it's gonna be like this everyday," he grumbled as he repositioned himself accross Boss' lap, burying his head in the pillow.

"Do You Want To Stop, Then?" Boss asked more seriously.

"pfff, do as you want," he said, his voice muffled by the pillow.

"Oh, Come On, Don't Be Like This. How About I Do This?" And he ran his fingers accross the lips of Sans' pussy, drawing a (reluctant) moan from him. "Would You Prefer That?"

Instead of answering verbally, Sans spread his legs further apart, raising his butt up so Boss' fingers had easier access. Boss hummed in pleasure and got back to his ministrations from before, only more vigorously this time. Just as he finally pressed one finger inside Sans, his other hand smacked his left cheek, the combination of the opposite feelings making Sans gasp. This time though, Boss didn't give enough time for the pain to settle in and massaged the ecto flesh, sending pleasant shivers up Sans' spine.

"hmm..." Sans moaned, wishing he could bury his head even more in the pillow.

Boss interpreted it as Sans' permission to continue, and began pumping his fingers in earnest, alterning between caressing Sans' butt and spanking it. Soon, Sans was panting and moaning, drool dribbling down his chin and staining the pillow.

"mmo- more! aah... hmmm! boss!" Sans blurted out, all embarrassment long forgotten as his body tensed from the pleasure of Boss' fingers in him and the burning feeling on his butt. "boss, i- i'm cl-! hmm! oh fuck!"

"Enjoying Yourself? Hmm, Do You Have Any Idea How Lovely You Sound Now?" Boss purred as he readjusted himself under Sans, who only then noticed the press of Boss' erection through his pants to his lower spine.

Ooh, how he wanted it in him.

Boss must've read his mind, as he removed his fingers from Sans' entrance, not without his complaint, and moved them so that he was behind Sans, his pants already open to let his cock free. He brushed the appendage a couple times over Sans' clit, making him hiss in pleasure, before pushing it in. He rubbed Sans' back and soon settled a restless pace. When he felt Sans relax again, he resumed the spanking, less hard then before, but more frequent. The left cheek, the right one, not a part of Sans' butt was spared the rough treatment.

"oh! fuck! b-boss!! yes! yes! more!" Sans nearly yelled, meeting Boss' thrusts.

It didn't take long for Sans to feel his climax approaching, and after two or three more thrusts from Boss, and a powerful slap on his ass, he felt his pussy tighten around Boss' cock, who followed him not too long after.

Even after they collapsed on the bed, Boss didn't stop massaging Sans' still summoned ecto butt, the transluscent flesh a dark red. They both caught their breath for a moment, Sans curling into himself a bit as he got comfortable with his face buried in the neck of his lover.

"So?" Boss asked quietly before Sans was completely gone.

"felt very good. can't wait for tomorrow," came the sleepy answer.

Boss smiled and placed a soft kiss on his sleeping lover's skull.


	3. day 2: dirty talk

Sans was staring at his plate of hotdogs in the mircowave, as if not leaving his eyelights from it would make his dinner heat up faster. He sighed as the device finally rang, his meal hot and ready. He sat at the table, pouring himself a simple glass of water.

Sans didn't like it when Boss wasn't home for dinner. He felt lonely and bored. He eyed his hotdog without any appetite and poked the bun.

"boss... come baaack," he whined.

He pushed his plate away, stretching his arms in front of him on the table, looking through the texts Boss had sent him earlier. He said he was going to be late because of royal guard stuff so Sans should eat first, but that he still wanted to do today's kink. Sans pouted, if this was how day 2 began, he couldn't even imagine how the rest of the month would be like. Granted it wasn't a good idea to begin this on a monday, Boss usually being quite busy at the beginning of the week, but it wasn't like they had decided on which day the month would start...

Leaning his head on the table, he texted a simple 'i miss u' to Boss, hopelessly wishing it could make Boss appear in the room right next to him.

Not even a minute after, his phone buzzed in his hand with a reply from his lover.

*Me too my love.  
*Have you eaten yet?

*nah  
*only hungry for ur sexy ass  
*♥

*Try to eat something please. It doesn't have to be a lot.  
*I don't want you to pass out tonight in the middle of our thing.  
*Do you want me to call?

*ye :3

Sans barely let enough time for his ringtone to ring and picked up. "hellooow?" He purred. "who's dis?"

"IT IS ME, PAPYRUS," came the very formal reply. So Boss was still at work.

Sans hummed, a little disappointed that Boss wasn't even on his way back home. How long would he have to wait?

"So Tell Me, What Did You Make Yourself For dinner?" Boss asked, his voice less booming.

"wait, can we really talk? i'm happy you called but i don't want to bother you during your job," Sans checked.

"It Is Fine. I Found A Somewhat Remote Place. Nobody Should Come Here," Boss assured him. Sans heard some papers ruffling as Boss continued, "Are You Really Not Hungry At All? What Did You Make For Dinner?"

"just plain old hotdogs. nothin' fancy," Sans answered as he brought his plate closer. He checked if it was still hot, and while it wasn't anymore, it wasn't cold either so he could still eat it.

"Hotdogs, Huh?" Sans heard the smirk in Boss' voice. "Does The Weiner Remind You Of Something?"

Uh, what?? Was Boss...

"w-what?" Sans stammered.

"Does The Weiner Remind You Of My Cock, Sans?" Boss clarified. "Long And Thick And So Hot For You."

"wow boss! aren't you still at work?" Sans asked, real concern that someone in the guard would hear Boss talk like this seeping in his voice.

"I'm A Master At Multi-tasking."

Boss laughed at Sans' baffled silence.

"Put It In Your Mouth."

Sans followed the instructions. He closed his eyes, imagining it was Boss' cock and hummed, letting Boss know he was awaiting for further commands.

"Good Boy. Now Suck It."

It didn't feel as good as the real deal, but it was better than nothing, Sans thought as he did as he was told, making sure to make enough noise for the phone to pick up.

"I Can't Wait To Be Home And Touch You..." Boss whispered, his desire clear in his voice, even as he forced himself to talk in a leveled tone.

"can't wait either. I want you boss," Sans said in a breath, pausing from his sucking.

"Yeah? Well, How About You Prep Yourself For Me, Hm?" Boss' husky voice whispered over the phone, sending pleasant shivers down Sans' spine. "Can You Do That For Me, Sans? Can You Put A Hand In Your Pants And Tell Me What You Can Feel There?"

Sans slid a trembling hand in his shorts, already feeling his magic gathering though still unsure of what to form.

"i-i feel my magic. still unshaped. should i make a cock or a pussy for you?"

"Well, Well, Well... You Know That I Am A Sucker For Anything That You Make," Boss answered playfully, and Sans didn't even have it in him to react to the unintentional pun. "Either Way I Am Going To Make You Feel Real Good. How About I Tell You What I'm Going To Do To You?"

"y-yeah? what are you going to do to me, boss?" Sans asked, not really sure if Boss wanted an answer or not.

"First, I Am Going to Lay You Down And Open Your Legs. I Will Want Them Spread Open So I Can See Your Lovely Pussy. Then I Am Going To Lick It, Until I Can't Tell If You're Wet From Cum Or From My Spit. If You Behave, I'll Even Let You Kiss Me So You Can Taste Your Own Juices On My Tongue."

"fffuck, boss, that's so hot!" Sans squirmed on his chair. He didn't know words alone could have this kind of effect on him.

"After That, I Will Probably Kiss Your Body, Your Ribcage, Your Neck, Your Cock. I Will Spend Time Swirling My Tongue Around The Head Until I Make You Scream In Pleasure. And When You Can't Take It Anymore, And Only Then, I Will Finally Take You, Slam My Big Cock In Your Tight Pussy, And I'll Fuck You For The Whole Night, I'll Make You Count How Many Orgasms You Will-"

"ooh boss! please, please come home! i want you now!" Sans pleaded, his magic reacting to his lover's voice by forming both sets of genitalia, doubling the sensations and making him feel light-headed.

"You Do, Now, Don't You?" Boss darkly chuckled. "Well, You Did Good So Why Don't You Go Upstairs To My Room? I Have A Little Surprise For You There."

"i don't fucking care about your surprise, boss! i want your cock in my pussy and your mouth around my dick!" Sans grunted, but still obeyed, climbing the stairs as quickly as he could.

He stopped dead in his track when he reached Boss' room though, opening the door only to reveal Boss himself, comfortably lying on the bed, his bare bones almost shining in the dark. And in the middle of everything, and what really drew Sans' attention, was Boss' cock, standing proudly erect and so, so good looking. Sans felt himself drooling.

"Well? Wasn't That What You Wanted? I Wanted To Surprise You And Came In Through The Windo- OOF!"

Sans didn't let Boss finish, running (yes, actually running!) to him and all but jumping on him. Honestly he didn't care about how or why or even when he had come home. All that mattered was that he was home now.

"fuck me!" Sans pleaded.

**Notes for the Chapter:**

> Okay so, I knew I wasn't really good at dirty talk in the first place, but seriously I didn't think I would suck so much. Honestly, it turned out okay-ish, but I swear you would laugh at how weak the first draft was...


	4. day 3: public

Boss slid his hand down Sans' ass as they entered the high-end restaurant, telling the waiter he had reserved a table for two. They were led to a nice table in a more private area. Boss had left clear instructions about the decorations and was pleased to see his orders had been followed to a T. The tablecloth was a rich red, Sans' favorite color, with countless candles all around the black silverware, and a beautiful white roses bouquet sat at the center of the table, making the whole place scream wealth and sumptuousness.

"wow boss..." Sans whispered in a breath. "that's... wow."

Boss couldn't help a smile, happy to see the small blush on Sans' cheeks. "Anything For You, My Love. To Apologize For Making You Eat On Your Own Yesterday."

"pff, you don't hav'ta apologize for nothin'," Sans replied, wrapping his arms around Boss' neck and standing on his tiptoes to give him a little kiss. Then he whispered so that only Boss could hear, "not after all those orgasms you gave me last night."

"Glad To Hear I'm Forgiven, Then," Boss said casually as they disentangled from each other to take their seat at the table.

The waiter, who had been politely quiet during the exchange, took their orders and finally left them. Once they were alone, Boss took out his phone and placed it in the middle of the table, tapping on the screen to open an app he had designed himself. "I Hope It Works."

"try on me first," Sans said.

"Okay, Ready?" He asked and when Sans nodded, he tapped a green icon on his phone. He watched attentively Sans' face, "So?"

The smaller skeleton closed his eyes and rested his head in his hands. "it works," he said with a satisfied grin.

Boss then tapped the second green icon on the screen and let out a quiet hum of pleasure as the ring around his formed cock began vibrating. He had been working on this for nearly a month and was glad he could have it finished in time for tonight. He had designed an app on his phone that he had connected to wireless chips that were inserted in the two dildos presently buried in Sans' ecto-pussy and wrapped around his own cock. All he had to do was press a button on the app and the dildos would switch on. If needed, he could even take the chip out and put it in another dildo.

Before coming to the restaurant, they had agreed to put the dildos on and have them running during dinner. Today's kink was to do it 'publicly', but because of Boss' position as a Royal Guard, there was no way he could even take the risk of being found doing naughty things with Sans, so that was the solution they had come up with. But honestly, neither would complain, the thrill of being pleasured like this in the middle of a highly frequented restaurant with the reassurance of no one being able to tell was really worth it.

The waiter then came back with their orders and a bottle of wine, fortunately not noticing anything that was going on under the table. Well, it was the plan, but seeing it going so smoothly was a relief. They began eating as they chatted about this or that, simply enjoying the moment together. Of course, they couldn't forget what was happening down there, but the basic settings were low enough to just be pleasant without being anywhere too much.

When he was done eating his dish, Sans took the phone and looked at it more closely. He wasn't very familiar with it, Boss being the only one having worked on it. "is there only one setting? i kinda want to, heh, turn up the volume."

Boss leaned over and pointed at the screen, "Here's The Button For Mine, And This One Is For Yours," he explained. "If You Tap Here, Wait, Let Me... There, You Have The Configuration Settings. You Can Turn It Higher Like That."

"so i can adjust yours too?"

"Yes, If You Want. But Can You At Least Wait Until I'm Finished Eating?" Boss asked.

"sure, sure."

Sans replaced the phone where it was and changed the settings of his dildo to a slightly higher setting. The reaction was immediate, he closed his eyes and let out a long sigh. Then Boss felt his leg being nudged and saw Sans opening his eyes and looking at him intensely. He hurriedly finished his starter and then turned his own dildo's settings higher, enjoying the feeling of the cockring vibrating more strongly.

The waiter came and went with their empty plates, bringing the rest of their meal, and by the end of their entrées, both Boss and Sans were seriously turned on. Not on the edge yet, but their breaths were indeniably ragged, especially Sans. Boss knew that Sans' dildo had more effect on him that the cockring Boss had. Sans had always been very sensitive when he summoned a pussy rather than a cock. Boss could see Sans wasn't too far from needing release, and turned his settings higher just as the waiter came back with their dessert. Sans let out a squeak, surprising the poor waiter who worriedly asked if Sans was alright.

"y-yeah, i... err oh! hmmm... i- hiccup!" He stammered as his body began trembling.

The waiter shot a glance to Boss for confirmation, and left when Boss just waved his hand dismissively. To be honest, reassuring the waiter was the last thing on his mind. The mere sight of Sans falling apart silently like that was a huge turn on for him.

Unable to hold it anymore, Sans pushed aside his plate and put his head on the table, his hands on each side. He began inhaling deep breaths as his body shivered more intensely. He gripped the tablecloth and let out a short but high pitched 'fuck', and Boss knew he just came.

Boss lowered Sans' settings, not completely switching the dildo off but just turning it to a low hum. After a quiet moment when Sans just caught his breath, his head still on the table, he sat back up. His face was flushed a deep red and sweat was beading on his skull.

"fuck boss. you just made me cum in the middle of a fucking restaurant," he whispered in an amused tone.

"So What?" Boss asked, as if it was the most normal thing to do.

"so we're going home so i can thank you properly," Sans replied, his dessert completely forgotten, standing up and taking Boss' hand to urge him to pay the check and go home as quickly as possible.

**Notes for the Chapter:**

> I have no idea if such a setup of app/dildo exists, I think the waves would be bad for your health. Still I thought it would be pretty cool if it did exist (and was safe).


	5. day 4: bukkake

"bukuku?"

"Bukkake."

Sans was looking at the list. He had no idea what buku- bake- buka- the fuck it meant. He didn't mind trying new things with Boss, but he at least wanted to know what they were about to do.

His confusion showed on his face apparently because Boss provided the explaination. "It's A Sexual Act Where Several Persons Ejaculate On Someone's Body. So Basically, You'll Be Covered In Cum. Litterally."

"wait, several persons? i don't-" Sans began.

"I Don't Want To Either," Boss interrupted. "I Don't Want Others To Be Intimate With Us. So We'll Skip The 'Several Persons' Part And Go Straight To The Point Where I Cum All Over Your Lovely Body."

Sans couldn't help a blush. He couldn't deny that he quite loved cum. Inside, outside, Boss' or his, just give him all the cum.

"sounds good to me," he said as he put the list back on the desk and went to sit on Boss' bed. "so, how do you want to do it?"

"Well, For The Time Being, Just Undress While I Prep Myself."

"yes boss."

Sans did as he was told, shoving his clothes in a shapeless lump and drawing a disapproving grunt from Boss. Then he sat on the bed again and waited for Boss to be done. He watched as the tall skeleton removed his clothes too, folding them neatly, and smiled when Boss went to stand in front of him, his hands on his hips.

Boss was beautiful, but when he was naked, he was even more stunning.

"You, My Lovely One, Are Going To Pleasure Me. Suck Me, Lick Me, Deep-throat Me, You Can Do Anything. Just Give It Your Best To Make Me Cum," Boss stated, wriggling his hips.

Sans didn't wait for further instructions and got on his knees in front of Boss, and immediately ran his tongue all over the front of Boss' pelvis. He delved it into the holes and creaks in his pubic symphysis, Boss humming in pleasure and running his hand on Sans' skull. With Sans' relentless ministrations, it didn't take long for Boss to summon his cock, already erect and ready to go.

"oooh, hewwo there, you. s'been a while, how have you been?" Sans playfully said as he nuzzled the ruby shaft.

"Pff, Stop That Sans, And Get To Work," Boss admonished him gently, trying to hide a smile and failing.

"aww come on boss, you're smiling!"

"I Am," Boss said as his grin widened. He gripped his cock and lined it to Sans' mouth. "But I Think You Should Use Your Mouth For Something Else Than Say Those Horrible Jokes."

Sans opened his mouth and shivered as he felt Boss penetrate him, the hot shaft brushing the top of his mouth. He immediately started sucking on it, bobbing his head up and down the rod, curling his tongue around it just the way he knew Boss liked.

Sans didn't lose time in being gentle, he straight up settled a restless pace, sucking on Boss' dick fast and hard. It wasn't often that Boss wasn't the one in charge of the tempo of their fucking, so Sans made sure to enjoy every second of it.

"Sans, I'm- Aah... C-close," Boss muttered after a while.

Sans released Boss' cock and began pumping it in earnest. Boss let out a grunt as his hand joined Sans' until hot and thick spurts of cum gushed from his cock and landed on Sans' face. The small skeleton closed his eyes, humming in pleasure at the feeling of his lover's hot juices trickling down his face.

"more..." He whispered as he opened his eyes again and the look on Boss' flushed face was enough to make him form a pussy on the spot.

Boss helped Sans on his feet and pushed him on the bed, straddling his hips and taking his cock in his hand again. He began pumping it, setting a rapid pace again. Sans joined him, one hand around his shaft and pumping with it, while the other caressed Boss' body, his legs, his ribcage, anywhere he could reach.

It took even less time for Boss to blow his load, this time spurting cum all over Sans' ribcage. Some of the cum dripped between the ribs, falling on the otherside of Sans' ribcage, coating even his back with the thick liquid.

But it wasn't over. After just a moment of catching his breath, Boss began rubbing his cock on Sans' dirty ribcage, the cum there making the shaft glide over the bones.

It only then occured to Sans just how much stamina Boss really had.

After a solid hour of Boss cumming on Sans, the tall skeleton all but collapsed on the bed next to Sans.

"Haa... Haa... I Think I'm... Done..." He panted. "Sorry Sans, I Didn't Want To Leave You Unsatisfied, But I Don't Think I Can Continue," he added as he gently caressed Sans' cum covered sternum.

"s'alright boss, just rest. i can take care of myself," Sans replied with a smile. It was the first time he outlasted Boss and that in itself was a turn on. And he didn't want to let the occasion slip.

He lowered his hand to his pussy and began masturbating while never breaking eye contact with Boss. After a minute, Boss' big hand joined him, his long fingers able to reach deeper than Sans' small ones.

"I Think I'm Awake Enough To Help You With This At Least," Boss purred while Sans moaned.

**Notes for the Chapter:**

> I know bukkake entails several persons, but I really really wanted to focus on just the fell bros, so plase forgive me.


	6. day 5: humiliation

Sans stood still in the living room as Boss finished helping him put the dog collar around his neck. He kept his chin up to give an easier access to Boss' fingers who closed the buckle.

"How Do You Feel? Can You Breathe Correctly?" Boss asked as he stood up.

"yeah, i'm fine," Sans replied, turning his head right and left to check from all the angles.

"I Had To Close It Over Your Turtleneck, So If Anything Feels Weird, Tell Me Right Now, Okay?" Boss double checked, just in case.

"everything's okay, boss," Sans assured him.

"Okay, Let's Go Then," Boss finally said as he opened the door.

Once they were outside and Boss had locked the door, he attached the leash to the collar that was now and for the rest of the night around Sans' neck. He tugged on it not too harshly, but strongly enough to make Sans tumble forward. He didn't seem pleased with the treatment but he said nothing so Boss began walking toward their destination, Grillby's bar.

He made sure to walk faster than usual so that Sans had trouble keeping up with him and had to half run awkwardly, his smaller legs not letting him walk as fast as Boss. But whenever Sans was too close behind him, he was sure to turn and push him back. 'I Don't Want My Dog To Walk Next To Me As If We Were Equals,' he'd say, and Sans would slow down.

They reached Grillby's in silence and entered the bar. It was Friday night, and most monsters from Snowdin were now free from work for the weekend, and were currently celebrating in the small establishment. Deer beer and alcohol were flowing freely and most patrons were already smashed.

In a corner of his mind, Boss thought it was for the best. He didn't particularly want everybody to remember him humiliating Sans tonight. If they were all drunk, it would be easier to later confuse them about it being just fantasies born from drunken minds.

The establishment was crowded but not packed, and Boss spotted a nice seat at a table on the side and went to sit there.

"What The Fuck Are You Doing?" He spat at Sans when he pulled the other chair to sit.

"u-uh? i..." Sans began.

"A Dog's Place Is On The Ground," he hissed and then tugged roughly on the leash, making Sans tumble over and crash on his knees on the floor next to the table.

"so-sorry," Sans stammered, confusion clear in his voice.

"Shut Up."

Sans then stayed silent. He sat correctly on the floor and put his hands on his lap. His head was bent down, his gaze focused on the floor.

Boss' attention was shifted to the heat suddenly coming next to him. Whipping his head around, he saw Grillby was there to take their order, but the elemental was eyeing Sans on the floor, rising a fiery brow in confusion. He didn't ask anything though, so Boss didn't say anything either.

"I'll Take A Glass Of Canine Wine, and some water for my dog," Boss asked as casually as he could. He couldn't deny it was awkward, the way Grillby's gaze was switching between Sans and him.

Grillby let out a sigh and nodded, going back behind the counter to prepare Boss' drink. He came back not too long after with Boss' wine and a pitcher of water for Sans. Boss thanked and paid him.

Boss took a sip of his wine and then checked on Sans, who was looking at him. "Are You Thirsty, Dog?" He asked in a leveled tone.

"yeah, i-"

"SHUT UP!" Boss yelled as he gripped Sans by his collar, drawing the attention of the closest patrons. "SINCE WHEN DO DOGS TALK BACK TO THEIR OWNERS?!" He released Sans and let him fall back on the floor with a loud thud. "If You Want To Drink, You Can Just Use Your Bowl."

And Boss took a metal bowl originally made for dogs from his inventory, dropping it carelessly on the floor. Then he took the pitcher and poured the water on Sans' skull, making him yelp from the sudden coldness. Boss let out a fake laugh and poured some in the bowl.

"There, You Can Drink Now."

Sans stood still for a moment, wet and cold despite the warmth of the bar.

"I SAID DRINK!" Boss shouted and put his foot on Sans' head, pushing him down roughly until he was just a breath away from the bowl. "Drink," he repeated threateningly.

Sans hovered over the bowl for a moment, not saying anything. Then Boss heard the sounds of a tongue lapping timidly at the water, and he removed his foot.

"Good Boy," he said condescendingly and finished his own drink.

He heard quiet whispers from the patrons and was reminded of everyone looking at them. He tried not to pay them any attention but it was hard, so instead he focused on Sans. The small skeleton was sitting silently on the floor, not moving. And his face was completely emotionless. Blank.

Nothing.

And it... wasn't a good sign. Boss didn't know why, but the sight gave him shivers. He decided it was time to go home and stood up, dragging Sans with him. He pulled on the leash once more and they were out of the bar in seconds.

Not even 5 minutes later, they reached their home and as soon as they were inside and the door was locked, Boss turned around to check on Sans, only to see huge tears streaming down his cheeks.

"SANS?! SANS!" He cried as he kneeled in front of the small skeleton, who only buried his face in his hands.

"red... red..." Sans muttered, his voice barely over a whisper.

Boss felt tears gathering in his eyes at the sight of his lover openly crying, heartbroken, repeating their safeword. Heart-wrenching sobs shook his small body. Boss wrapped his long arms around him and delicately carried Sans upstairs to his room. He placed him on the bed, still in his clothes, and threw the covers over them both.

He let Sans cry himself out until he only let the occasional sniffing out, all the while caressing his back soothingly. When he felt Sans had calmed down, he whispered, "I'm Sorry Sans, I'm Really So, So Sorry." He kissed his forehead and hugged him tightly, making Sans whimper weakly in his arms. "Sans, My Love, Why Didn't You Say The Safeword If You Didn't Like It?"

Sans stayed silent, but wrapped his arms around Boss, burying his head deeper in his broad chest.

"Sans, Please Tell Me. I'm Truly Sorry I Hurt You."

"i... i don't know... i wanted... 'm sorry boss..." Sans' voice was so small, so weak, it sent fresh tears to Boss' eyes. He sounded so broken and defeated.

Almost guilty.

"Sans, My Love," Boss said firmly, taking Sans' head and tilting it up so he could meet Sans' wet gaze. "You Don't Have To Apologize. You Didn't Do Anything Wrong. It's My Fault For Not Realizing Just How Uncomfortable You Were. Okay?"

Realizing Boss was waiting for a reply, Sans gave the tiniest of nods.

"You Can Say The Safeword Whenever, And I Mean It, You Don't Like What I Am Doing. It Can Be Absolutely Anything. I Won't Get Angry, I Won't Get Mad And I Will Stop. Okay?"

"hmm..." Sans said, new tears rolling down his cheeks.

Boss kissed him sweetly and then got out of the bed to take the kink list on his desk. He grabbed a pen and went to sit on the bed next to Sans. "Look," he said, "I'm Crossing Today's Kink From The List. I Don't Want To Do It Ever Again." He showed the list to Sans and was glad to finally see a tiny smile on his face.

"what about you?" Sans asked when Boss was back in the bed. "did you enjoy it?"

"It Doesn't Matter," Boss answered curtly.

"no, i mean... i'm curious," he clarified.

"Hmm... Not Particularly."

Sans smiled.

"can you... say that you love me?"

"I Love You," Boss said without hesitating.

"me too," Sans said as he hugged Boss tighter and closed his eyes, sleep following not too long after.

**Notes for the Chapter:**

> :(  
> I don't like humiliation kink, and fortunately the dice agreed with me and gave me a NO for Sans. I don't know if I would have been able to write this chapter otherwise. (I'm not even sure what I wrote can actually be considered humiliation kink...)


	7. day 6: size difference

Boss licked across Sans' chest, making him moan and jerk underneath him. He tightened his grip around Sans' wrists and used his free hand to fondle his pelvis.

"ooh boss!" Sans whined with a shiver. "please, more..."

Boss smirked. He had to take extra care in prepping Sans today, but at the same time, he didn't want him to form anything just yet. So he just continued licking his ribcage as he caressed his pelvis, making sure not to touch too close to his most sensitive spots.

"please, please..." Sans begged again.

"Shh... It's Okay Sans, Just Relax... I'm Going To Make You Feel Really Good," Boss promised.

He released Sans' wrists and positioned himself just in front of his pelvis. He caressed the bone for a moment and then began licking and sucking everywhere his tongue could reach. He lapped the smooth surface, drawing hot moans from the small skeleton who tried not to squirm too much, failing miserably.

Boss pulled away just as Sans' magic began manifesting, unable to take shape.

"fuck boss! that's mean!" Sans complained, propping himself up on his elbows.

"Stop Whining," he replied, rolling his eyes. "I'm Going To Be Lenient And Let You Choose What You Want To Form. Just Remember To Make It As Small As You Can."

While Sans was focusing on his magic, to form a pussy Boss saw from the corner of his eye, Boss directed his attention on his own agitated magic. Summoning genitalia was a natural, unconscious thing for skeleton monsters, and being a non-fleshy species, they could give any shape to their magic. So they could form either a penis or a vagina, but it also meant they could decide of the size of their summoned genitals. However, the more different it was from their most naturally summoned parts, the more complicated it was to form. Boss for instance was used to form a long cock with an average girth. If he were to try forming a small vagina, it would take him more concentration, due to the lack of habit of summoning such genitalia. Sans on the other hand was used to forming both a penis and a vagina.

"wow boss, that's... huge," Sans hesitated, his eyes wide open as he looked at what Boss had just formed.

Boss' newly summoned dick wasn't that much longer than usual, but it was considerably larger. It stood erect between Boss' legs, ready to go. Boss pumped it a few times, glad that the feeling wasn't too different from his usual size. He didn't get to toy with manipulating his magic to change it very often.

Once he lifted his head to see Sans' pussy though, he had to stop to consider the size of it. It wasn't tiny, but it was definitely small. Very small. Would he fit? Would he even be able to enter?

"Hmm..." He hesitated. "Let Me Just Grab Some Lube."

He went to the closet and brought back a tube. He squeezed a very generous amount of the lube in his hand and covered his cock in it, pumping it a few times for good measure. Then he bent down and began licking Sans' small pussy, running his tongue over the clit and between the lips. He smeared as much spit as he could all over Sans' entrance, making him moan loudly without meaning to.

He sat up again and lined himself with Sans' entrance, not pushing it in just yet though. He looked at Sans, who seemed about as much unconvinced as him of the fact that it would fit.

"maybe... put some lube on me too?" Sans tried.

"Yeah..."

He squeezed the tube until there was no lube left, spreading it on Sans' magic and putting some more on his own, just to be sure. Then he lined himself again and slowly, very slowly and very carefully pushed inside, constantly checking on Sans. The head was barely in when Sans' breath sped up and he tapped Boss' arm, making him stop.

"boss, wait, wait..."

"What? Did I Hurt You? Are You Okay?" Boss asked, concerned.

"i-i'm fine. i just need some time to... adjust," he whimpered as he closed his eyes and let out a long sigh.

"Sure," Boss said and caressed Sans' body to help him relax.

He tried not to pay attention to the way his cock was squeezed tightly by the walls of Sans' warm pussy, making it hard to think. But Sans' wellbeing and pleasure came first, so he ignored his cock's constant throbbing.

Boss watched as Sans licked his fingers and lowered his hand to play with his clit. His squirming made Boss' cock move inside him, drawing a grunt from the tall skeleton who closed his eyes, only to open them again when he felt Sans lift his legs to place them on Boss' shoulders. He gripped the ankles and carefully pushed inside a bit more, one of his hands joining Sans' fingers on his clit.

Once he was hilted inside, Boss bent down again and kissed Sans thoroughly, the small skeleton wrapping his arms around his neck to keep him close. Boss began moving out slowly, Sans pulling back from the kiss to let out a sigh.

"Y-You Okay, My Love?" Boss checked.

"hmm, fuck that feels good."

Boss smirked and rolled his hips forward again.

"oh fuck! more! do that again!" Sans yelled, his back arching and his hands gripping the sheets.

That was all Boss needed to know. He set a punishing pace, his huge cock slamming in and out of Sans' tight pussy hard enough to make the bed creak. Despite being usually silent, he couldn't help letting out loud moans which were no match to Sans' ones, who all but screamed with each thrust forward.

It was too much, the tightness of Sans' pussy and how he was writhing under him, his moans of pleasure and the lewd sounds of their magic slapping together. Boss felt his climax draw near and went to massage Sans' clit again, who only reacted by spreading his legs even further apart. The sight of Sans litterally offering himself to Boss was enough to push him over the edge, and he buried his cock one last time inside Sans' pussy before cumming hard, his loud grunt drowning down Sans' own shout of pleasure.

Boss collapsed on the smaller skeleton's ribcage, too spent to move to his side and barely able to ask Sans if he was doing okay.

"Sans?" He repeated when there was no answer.

He opened his eyes he hadn't even realized he had closed and lifted his head to look at Sans, who had the biggest grin on his face. Well, at least he was okay.

"Sans? You Okay?"

"fuck i still can't believe it fit!"

"It's Still Inside, You Know."

**Notes for the Chapter:**

> Not my best because it's not a kink I'm really into, and also because I wrote it while I was half-asleep. Meh.


	8. day 7: creampie

 

"yes, yes, yes..." Sans chanted wich each one of Boss' thrusts.

His pussy was on fire, his bones were trembling, and his mind was going fuzzy, but still Boss didn't slow down. Sans couldn't remember for how long they had been fucking, but he didn't want it to stop. How he could still be going, even after cumming so many times, was a wonder.

He cried out when Boss began playing with his clit and he wrapped his legs around the taller skeleton's middle.

"fffuck... boss, i-i'm gonna cum, i'm gonna cum," He moaned, his breath hitching on every word.

"Then Cum For Me, My Love. Cum All Over My Cock," Boss grunted, not too far from his own climax.

Sans didn't know if it was Boss' permission or the sudden speeding up of the pace that did it for him, but he felt his pussy tighten once again around Boss' cock. His body arched under Boss and his legs jerked around him, his toes curling on themselves. He let out a loud moan and inhaled deeply when he felt his body relaxing again. He knew though that it wasn't finished, not when Boss had such a devilish look on his face. Sans yelped when Boss kept massaging his clit, overstimulating him to the point where tears welled up in his eyes. He tried to remove Boss' hand from his magic, but was batted away easily.

"What's Wrong, My Love? Do You Not Like It When I Touch You Like This?" Boss teased, not stopping his ministrations.

"f-fuck you..." Sans weakly replied without any bite at all.

"Oh? So Then You Prefer If I Just Stop?" He said, feigning disappointment, as he drew away his fingers slowly.

"no!" Sans shouted without meaning to. "ah, no, i mean... just..."

Embarrassment burned his face, his deep blush probably bright enough to light the darkest cavern of Waterfall. Boss chuckled darkly as sans hid his face with his hands. Why did Boss always had to be such a dick and tease him so much? He didn't know anymore if he wanted to continue or stop. Thankfully, Boss made that decision for him when his fingers were back on his over sensitive clit.

"What, Sans? Tell Me What You Want Me To Do," his growl sent a shiver down Sans' spine.

"i... i want..." He began, but honestly at that point he didn't know anything anymore!

"Yes?" Boss prompted as he pinched the delicate nub of magic, making Sans cry out.

"fuck! fuck me, fuckmefuckmefuckme!!!" Sans snapped.

Then Boss deftly turned his over so that he stood on all four, without even pulling out. The rotation reminded Sans of how Boss was still hard inside him and made his moan again, his body reflexively bending down to give easier access to Boss, who didn't leave enough time for Sans to comprehend what was happening. Before he had the time to ask what was going on, Boss was back to thrusting into him, pounding him into the mattress. Boss pressed Sans' back down while keeping his ass up in the air, the angle making Boss' cock reach deeper into Sans, brushing that lovely spot that made him see stars.

"right there! yes!!" Sans yelled, unable to think.

"FUCK! SANS! YOU FEEL SO GOOD!" Boss joined him, cursing loudly as he sped up the pace yet again.

Their room was a mix of Sans' moans, Boss' curses and the wet slapping of Boss' cock into Sans' pussy, thick and hot cum from their previous orgasms spilling out and dropping on the dirty sheets. It all went quiet suddenly with a particularly deep thrust of Boss' hips, making Sans come in a silent cry and Boss grunt, his usual self control thrown out the window a long time ago.

When Sans' body relaxed and threaten to fall flat on the bed, Boss kept him from falling by sliding his arms under his ribcage. Then he carefully turned him over again so that Sans laid on his back and put a pillow under his head for support.

After they caught their breath for a moment, Boss asked in an intentional whisper, "How Many?"

"at least 8 or 9," Sans answered with a more than satisfied smile.

"Something Like 7 For Me. So That Means You Should Be Quite Full Of Cum In Here," Boss said as he caressed Sans' swollen belly. "You Ready For Me To Pull Out?"

"yeah," Sans said as he propped himself up on his elbows to have a good view on where they were linked.

Slowly, Boss began to pull out, a large quantity of cum spilling from Sans' pussy in the process. When he was totally out, the thick liquid continued to flow for a moment.

"can i suck you?" Sans asked, eyeing Boss' cum covered cock with a ravenous look and licking his teeth.

**Notes for the Chapter:**

> Sorry it's kinda short, especially compared to the previous ones. I had trouble with the kink itself, which is short when you think about it? idk...


	9. day 8: latex

Sans slowly opened his eyes, yawning as he slowly woke up from his nap. He had fallen asleep earlier watching Boss work on his desk after they had dinner. Boss had come home late, and Sans had prefered to have a quick nap in order to be fully awake for tonight's activities.

(It had happened to him to fall asleep while fucking once because he really was very tired, and Boss hadn't appreciated...)

Sans looked around, not spotting Boss at his desk. He called him and straightened his back before getting out of the bed. He was about to leave the room when the door opened, revealing Boss.

"Ah, I Thought I Heard You. Slept Well, Fuckface?" He asked.

"until i saw your ugly face, yeah," Sans replied and opened his arms to hug Boss.

"Are You Read For Tonight's Activity, Then?" Boss checked after the hug.

"yup!"

"Come With Me, Then."

Boss took Sans' hand and guided him to Sans' former room. It had been a long time since Sans had moved in Boss' room, and since they didn't really need another bedroom, they just left it as it was. Boss still cleaned it from time to time, and Sans still used it to take naps, though very rarely. So Sans was surprised that Boss would lead him there for the night.

Upon entering the room, Sans could see that nothing much had changed since the last time he had come in. There were clean sheets on the bed, but that was it.

"why are we here, boss?" He asked.

Boss entered and began to undress as he answered, "I Plan On Using A Lot Of Lube Today, And I Don't Want To Do It On Our Bed. The Lube Might seep Into The Sheets And Stain The Mattress. So I Cleaned The Room A Bit And Put Fresh Sheets While You Were Resting. If It's Going To Be Dirty Anyway, We Might As Well Get Your Already Dirty Mattress Even Dirtier." Once he had folded his clothes and put them in a neat pile next to the door, he put his hands on his hips. "Now Undress While I Get What We Need, Would You?"

"sure boss."

While Sans was getting rid of his clothes, Boss went to Sans' unused desk and retrieved a new bottle of lube and what looked like a pile of red and black clothes made of a shiny fabric. Now naked, Sans went to sit on the bed, looking at Boss putting on a pair of very shiny and VERY tight black pants, and an equally shiny and tight red tank top. It didn't look like leather now that he was thinking about it, and if Boss had had to use lube...

"is that made of latex?!" Sans suddenly asked in an epiphany.

"Well, Yes. It IS Today's Kink After All," Boss said as he turned around, showing off his body. The clothes really highlighted how sexy Boss really was, and Sans felt his magic react by stirring in his SOUL. "What Did You Think We Would Do Tonight?" Boss asked, drawing Sans back to reality.

"i don't know... maybe do it with a condom?" He tried.

"I'm Not Really Sure It Would Qualify As Latex Kink..." Boss said thoughtfully.

"oh, but this is way better!!" Sans hurried to say. There was no way he was letting Boss remove that outfit, he was way too damn sexy in it.

"Good To Know." Then Boss gave the other outfit to Sans, a set of sexy lingery with thigh high boots, everything made of latex. "Here's Yours. Put Some Lube On And I'll Help You Put It On."

The two then took some time to finish getting ready, Boss helping Sans put on his outfit and then finishing putting on his own. Boss added to what he was already wearing a nice black jacket with edgy spikes on the shoulder pads, and leather boots that came up to his knees and that he buckled over the pants. He struggled for a moment with his fingerless latex gloves and even wore a latex peaked cap that perfectly completed the look.

Fuck, Boss was goddamn sexy.

Sans was too enthralled in Boss' appearance to notice the look of lust on his face. Boss gently pushed him on his back and climbed on the bed to hover over him.

"Do You Have Any Idea Just How Sexy You Are?" Boss rasped, his voice husky with arousal. "We Haven't Done Anything Yet But I'm Already So Hard..."

Sans shivered from Boss' deep and gravely voice until he processed what he had just said. "m-me? sexy?"

"Oh Fuck Yes. You're Hot And I Want To Do Dirty Things To You," Boss continued as he bent down to place surprisingly light kisses down Sans' neck.

Sans blushed profusely from the praise. He didn't have a high opinion of his physical appearance and didn't consider himself a sexy or beautiful monster, far from that. So whenever Boss called him hot, or cute, he just melted and couldn't stop blushing like a fucking highschool girl. It was so embarrassing, but at the same time, he loved it.

He lifted his head, humming as Boss continued to lick his neck bones, and lifted his legs to put one over Boss' back, the latex clothes rubbing together.

_squeak_

Boss moved from Sans' neck to his ribcage, tracing more languid kisses everywhere and running his gloved hands all over Sans' body.

_squeak squeak_

Sans felt a smile tug at his mouth, but was soon distracted by Boss pressing his body on his, humping him and Sans felt the other's erection through his pants, his mouth watering...

_SQUEAK_

...until Sans couldn't hold it anymore and bursted out laughing, startling Boss whose eyes opened comically, not helping Sans at all.

"Sans? What?"

Sans tried to explain, but he was too busy wheezing with laughter, clutching his middle, but the mere sounds of his arms rubbing with his ribcage was enough to send him into another fit of laughter.

After a moment of Sans just laughing non stop, Boss sat up and let out a flat, "Sans. Shut The Fuck Up." Sans calmed down enough to see the displeased look on Boss' face and he tried his best to stop laughing. "What's So Funny? I'm Trying To Work Here!" Boss complained, crossing his arms, the latex squeaking again as it rubbed and making Sans snort.

"THAT'S IT! I'M DONE HERE!" Boss fumed as he climbed down the bed.

"b-boss! sorry!" Sans caught his hand before Boss was gone. "i swear, i'm sorry! i just- it's the sound. snrk. it sounds like farts and it just... pfff! it ruins the mood, ha ha ha!!" And Sans was gone again, tears welling in his eyes from his laughing.

His laughter was contagious, and Boss couldn't suppress a smile as he stiffled a laugh with his hand.

"really boss, i'm sorry but it's just not gonna work!" Sans tried to say but it sounded more like a sick mouse squeaking, his naturally deep voice twisted in a high pitched squeal by his laughter. "maybe if we're not both wearing latex at the same time?" He managed to get out. "because fuck, you look sexy, and i'd be forever damned if you never wear this again because of me..."

"Do You Have Any Idea How Much It all Cost Me?" Boss half grumble, half giggled.

"uhh... sorry... boss..." Sans whispered as he recovered from his laughter, panting breathlessly. "but i can't..."

Boss stood in the middle of the bedroom awkwardly for a moment until he just let himself fall on the bed, sighing.

"To Think That I Worked My Balls Off To Clean This Room..."

**Notes for the Chapter:**

> The dice gave me not one but 2 NOs for this kink and it was honestly hard to find a reason for both of them to not like it. Until I watched a video about how to properly care for a latex outfit and I heard the sounds. I'm sorry if I'm ruining it for anyone, but it made me laugh so hard, I HAD to include it in the fic. (that being said, latex outfits are so fucking sexy)


	10. day 9: asphyxiation

**Notes for the Chapter:**

> Asphyxiation is a dangerous kink that can cause very serious damage to your health if not done properly. Sans and Papyrus are fictional skeletons made of magic, so this fic is in no way a guide for you to learn (that goes for any kind of kink, not just asphyxiation). Please do real research before trying it on yourself/your partner.  
> Stay safe! ♥♥♥

Boss was quiet with concentration as he was reading for the umpteenth time the book in his hands. Sans was pressed next to him, unusually silent. Both knew how important it was for Boss to read the book thoroughly, both for safety reasons and for his peace of mind. Today's kink was a relatively dangerous one when not done properly, and Boss wasn't one to put Sans' life in danger when he could prevent it just by doing some research.

Contrary to popular belief, even skeleton monsters could suffocate. While it was extremely rare on its own, it wasn't unheard of for a monster to attack a skeleton and asphyxiate them. All the attacker had to do was to apply a tight pressure on the skeleton's neck while sending malevolent magic which would cut the flow of the skeleton's own magic. It wasn't 'asphyxiation' per say because there was no air involved, but the feeling was quite similar. Denied their access to their magic, the skeleton would have no mean to protect themself but physically, and if extended for a long period of time, it might even result in the skeleton's death.

Which, of course, wasn't what Boss and Sans were going for tonight.

So Boss had spent the entire day looking through every book they had about skeleton anatomy, which unfortunately wasn't a lot, and doing research about the subject. He had tested it a few times on himself, to see what it felt like, how long he could do it before feeling it was really dangerous, how much pressure he'd have to use... The more difficult part would probably be sending his magic with enough hostile intent to cut Sans' magic, but still not too hostile not to do real damage to Sans' health. They had no choice but to start small and do it little by little on this one.

Boss closed the book in his hands and let out a long, heavy sigh.

"Sans. This One Is Dangerous. Like, Really Dangerous. Especially For You."

"i know boss. but i trust you. if anything feels like it's gonna go wrong, i'll say the safeword or click my fingers. i promised you," Sans reassured him as best as he could, hugging him tightly.

"I Know I'm The One Who Chose The Kinks, But I Just Want To Make Sure You're Safe," he said as he placed a kiss on the top of Sans' skull, returning the hug.

"i am safe, boss."

The two then went upstairs, undressed and got comfortable on Boss' bed. Once they were both ready, having shared kisses upon kisses and hot caresses, Boss curled his fingers around Sans' throat, focusing on his magic but before he could try suffocating Sans, he felt the small skeleton tap gently his side. He immediately panicked and removed his fingers, running check after check to his fragile lover and pestering him with questions about any pain or discomfort.

"no! no! relax boss!" Sans had to hurry to say before Boss would explode. "calm down! it's not gonna work if you're too worked up. and, i mean... i'm not sure i'm going to enjoy something so rough if you're so gentle otherwise."

"What? What Do You Mean?" Boss asked. He was gentle because he didn't want the experience to be too overwhelming for Sans. And also because he was actually kind of scared, but there was no way he would tell Sans, to not stress him any more than he probably was.

"i mean that i want you to fuck me hard, and then in the middle of that to choke me. i don't want gentle right now, i need you to destroy me," Sans explained, unable to hide his blush. Was it from embarrassment or arousal, Boss didn't know, but it was probably a mix of the two. That was certainly how Boss was feeling right now.

"Oh."

Well, that was something Boss knew how to do. He didn't lose time in overthinking it and just delved into the fucking Sans part, ravishing Sans' mouth in messier kisses and taking his cock in his hand to pump it a few times, making himself hard. He brushed the tip of his cock to Sans' own dick, smearing the bead of precum that was sat at the top. He continued to stroke himself, his hand nudging Sans' cock from time to time, while Sans busied himself playing with Boss' ribs, enjoying the grunts of pleasure Boss made whenever he pulled at one of the lowest ones. He crooked his fingers at the back of Boss' ribcage, where the ribs connect to the spine, distracting him from his jerking off.

That was a pace they were both more used to, and so it didn't take long for Boss to feel his climax approach. But he wanted Sans to be the first, so he swapped his cock for Sans' smaller but girthier one, stroking him fast and hard, drawing a sudden cry from him.

"oh fuck, boss! yes, yes yes! that's it, hmm, i love it!" Sans chanted as he bucked into Boss' hand for more friction.

"Sans, I'm Gonna Try It," Boss warned, wrapping his free hand around Sans' neck again.

Sans looked at him for a few seconds, a clueless look in his eyelights, until it came back to him and he smiled, nodding and then tilting his head up to show it was okay for Boss to continue. Boss tightened his grasp of Sans' neck, feeling the bones resist him, and he channeled his magic into his hand. Despite his best efforts, he wasn't able to sum up enough (or any for that matter) harmful intent for what he wanted to do, but it seemed regular magic was enough to do the trick, because Sans reflexively opened his mouth as if to breathe, but nothing went in or out. After 5 seconds, Boss let the pressure down on his neck, and Sans inhaled deeply a few times before a huge grin spread on his face.

"fuck, boss, that felt so so good, you have no idea! do it again, please, do it again!!"

Reassured to see Sans wasn't hurt and feeling smug that he even wanted more, Boss did it again, applying a tad more pressure than before. At the same time, he sped up his pumping around Sans' shaft, feeling it swelling in his hand. Sans was close. He began flailing his arms and trashing his legs under Boss, who suddenly let go of the pressure around Sans' neck. The feeling of his magic returning to his senses and coursing through his body again so suddenly did it for Sans, who came into Boss' hand with a keening shout.

Boss let Sans catch his breath for a moment before asking him how he felt. He didn't want to interrupt Sans' afterglow, but he needed to know he was okay.

"i'm... fine, boss. more than fine. heck, that felt fucking awesome!" Sans managed to say after a while. He still sounded tired but had a huge smile on his face. "do you think you could... do it again?"

"Sans, I... I Didn't Like It," Boss said with an apologetic smile, averting his eyes. "I'm Sorry, I'm Just Too Scared Of Hurting You Unintentionally..."

"hey, boss," Sans's suddenly serious tone grabbed his attention. "it's okay. it was wonderful, but if you don't like it, i won't force you. okay?"

Boss couldn't resist hugging Sans, and all but crushed him into his arms.

"you didn't get to finish though, right? how about i help you with that, hm?" Sans asked with a grin after a moment, running a teasing finger up Boss' still summoned cock.

"I Wouldn't Be opposed To That," Boss answered as he turned them around so Sans was lying on top of him. "I Mean... There Are Other Parts Of My Body You Can Choke On Besides My Hands."


	11. day 10: edgeplay

**Notes for the Chapter:**

> Trigger warnings in end notes.

Boss was sat on the couch, lost in his mind. He was waiting for Sans to finish showering so that they could start tonight's game. His SOUL sped up at the thought.

Today's kink was edgeplay.

When he was looking for interesting kinks on the undernet for the kink list, he came across this one quite a few times and decided to include it. But the more he did research on the subject, the less he felt he could actually do it. Especially given how yesterday had gone. Asphyxiation had already made him uncomfortable, and to think it was just a part of edgeplay...

But he had to try, right? That was what the list was for.

And Sans had enjoyed asphyxiation. Boss had made the list to please Sans, with kink that he might enjoy, so no matter how uncomfortable it made him, he had to do it. For Sans.

Since edgeplay was a large term encompassing more precise activities, he had had to chose what he would do tonight, and had decided to use a knife. The most common plays he had came across in his research were breathplay, bloodplay and humiliation play, but they had either already tried it, or it was on his list for a later day. Another interesting one was rapeplay, but he couldn't really figure out how he would be able to fake rape when Sans was usually so willing to participate.

When they had discussed it with Sans, the small skeleton had suggested he used knives, because due to his job, Boss had become quite the master at using them, especially for threatening purposes. It would just get some creativity to go from threatening enemies to teasing a lover, but nothing Boss couldn't handle.

"boss?" Sans asked, startling him. He hadn't even heard Sans get out of the bathroom. "are you okay?"

"YES," he answered maybe a bit too quickly.

For Sans, Boss thought to himself.

He led them to his room and didn't lose time in undressing Sans. He kissed and caressed every bit of Sans' body he could, licking the freshly clean bones and inhaling Sans' smell. There was a particular scent to him that was spicy and sweet at the same time, and it never failed to turn on Boss. His cock formed in his pants as he pushed Sans toward the bed, but right before Sans could even bend down to sit on it, Boss flipped them around so he was behind Sans, the small skeleton's back pressing against his ribcage.

"boss? what the- ah!" Sans began but was interrupted when Boss began licking the nape of his neck.

Sans lifted his arms and reached behind to wrap them around Boss' neck, pushing himself up to climb on Boss' lap. Then he wriggled his hips, making Boss grunt from the friction between Sans' bare sacrum and his clothed erection. Boss noticed Sans still hadn't formed anything yet, but not for long, he thought as he lowered a hand to fondle his pelvic bone. He crooked his fingers around the pubic symphysis and felt Sans' magic swirl around his fingers, a clear signal that he was aroused enough to form something. He let him decide what kind of genitalia he wanted and instead opened his inventory to take out the knife he was going to use.

It was a beautiful dagger that he very rarely used but always carried with him. It was originally a present from Sans that he had gifted him when he joined the royal guard, as a congratulation for finally achieving one of his biggest dreams. It seemed fitting that Boss would use it today.

Once he had unsheathed the blade, he used his free hand to tilt Sans' head toward him and kiss him thoroughly, swirling his long tongue with Sans' broader one. While he was distracting Sans with the kiss, he lowered the knife until it was almost touching Sans' ribcage.

For Sans.

He thought about how he usually did with his prisoners, but a lot of more than unpleasant memories flashed in his mind that he absolutely never wanted to link with a night of intimacy with Sans.

So he focused on what he knew Sans liked. He always enjoyed when Boss scrapped his fingers on his sternum. But would it be the same with a knife? Wouldn't it hurt too much and actually damage his health? Sans only had 1 HP so Boss couldn't be careless.

No matter how much he hated the idea of thinking about his job during a session with Sans, he tried to recall the times he had to torture prisoners. He usually started on the sides of the chest, digging his knives along the flesh to leave deep scars that would hurt for as long as the prisoner would breathe. He would make sure never to lighten the pressure too much, the blade in constant contact with the prisoner's flesh. In the case of a non-fleshy monster, quite rare in Snowdin but not uncommon in Hotland, he would just drive the knife in, very slowly until his ears would ring from the prisoner's cries.

He felt the prisoner wriggle and tightened his hold. Letting them escape wasn't an option. He felt the pulse of their magic speed up and chuckled darkly. He felt fear emanate from their magic, and they had a good reason to be afraid of him. He was the most dangerous member of the royal guard, known for his extremely high Lv, who dealt with executions on a daily basis.

He opened his eyes and locked his gaze with...

with Sa

  
WITH SANS

 

 

 

  
HE WAS HURTING SANS HE WAS HURTING SANS  
HEWASHURTINGSANSHURTINGSANS

  
boss!

 

 

  
boss!

 

"papyrus!"

  
"breathe with me"

"in"

"out"

in

out

"that's it, boss. slowly"

in

out

 

 

"red, boss. okay? i'm okay. it's okay," he heard Sans say.

  
"it's okay"

"i'm okay"

  
You're Okay

  
He dropped his knife and heard it fall on the floor.

"You're Okay," he croaked.

His breath was still ragged, his vision still blurry with tears. And he was trembling so much.

  
But then Sans hugged him and everything felt better.

**Notes for the Chapter:**

> Trigger warning for: panic attack, scene gone bad, use of safeword, it's just not a happy ending.
> 
> How terrible the dice gave me a NO for the kink on my birthday (and a kink I'm not fond of in the first place). I really wanted to include outcomes like this (or like day 5) in this fic, because when you explore new kinks with a partner, it's bound to happen at some point.  
> I also want to point out that Boss was in the wrong mindset from the moment he thought "no matter how uncomfortable it made him, he had to do it. For Sans." You NEVER 'have to' do something for your partner (sexually I mean) that makes you uncomfortable. It's just not gonna work. Just talk to your partner until you're comfortable with it (like setting boundaries or rules or whatever makes you feel better), or until you both agree that it's not something you want to do/try.
> 
> Once again, stay safe! ♥♥♥


	12. day 11: sadism masochism

"how are you feeling?" Sans asked as he put the tray he was carrying on the nightstand. "i brought you some coffee."

Boss slowly sat up, his head spinning and killing him.

"I wouldn't say no to some pain killer," he croaked, his throat sore.

"sure, boss."

Sans poured some water in a glass and handed it to him. He sighed when he finished the drink, but instead of getting up, he just lied back down. Sans caressed his cheek tenderly and then took the cup of coffee for himself before sitting on the floor to be at eye level with Boss.

"i called undyne and told her you were sick. you have the day off so you can rest. i have to go to my station so if anything's wrong, just call me, okay?" He said when he was finished with the drink, standing up to take the tray back to the kitchen.

"Sans," Boss called out before the smaller skeleton was out of the room, catching his attention. "Thanks. I love you."

"i love you too, boss!" He answered without missing a beat, a huge grin on his face.

"See you tonight?"

"sure!"

Boss closed his eyes again when Sans closed the door, listening to his footsteps going away in the hall.

His head was still hurting, but it was already way better than when he had woken up in the middle of the night. It had to be expected though. After yesterday's failure, he had fallen asleep crying in Sans' arms and had horrible nightmares all night, until he had waken up screaming Sans' name in the dead of the night. It had taken him a good hour to calm down enough, Sans thankfully remained calm enough to explain he had had a bad panic attack during their play but that everything was fine now. Then they had both fallen back alseep for the rest of the night.

But Boss was still exhausted, so it was a good thing that he had the day off. He didn't like to skip work, but honestly he didn't feel like going to work today at all. He probably would have another panic attack. He wasn't one to abuse his rights and was so rarely absent that he didn't feel bad not going today. He needed the day off.

He must've fallen asleep again because the next thing he knew, Sans was sprawled over the bed next to him, a book in his hands. He yawned and that caught Sans' attention, who closed his book and placed it on his nightstand.

"slept well, assface?" He asked in an amused tone.

Boss snorted. "Until I Saw Your Adorable Face," he replied, not used to their little exchange in this order. Sans was usually the one outsleeping him.

Sans thought the same and laughed. "nah, you're not supposed to say something nice, boss! you have to call me fuckface or something."

"But You Are Cute."

"pfff, oh you!" He laughed and climbed on Boss to kiss him. When they parted, his face had a more serious expression. "should we address the elephant in the room?"

"You're Not That Fat," Boss said, earning a playful nudge from Sans.

"shut up!" Then Sans sat up, crossing his legs. "i meant today's kink. it's supposed to be sadism and masochism, but... seeing how yesterday went, i don't think it's gonna work."

"You're Right. I Don't Think I Could Do It Even If I Wanted To," Boss confirmed.

"it's okay, we can always try at a later point, when you feel better. or we can just forget about it altogether. did you have something in mind?" Sans asked and Boss thought about it.

"Well, I Bought A Whip. I Was Also Thinking About Trying Clamps. But Yeah, I Guess It Can Wait."

A loud grumble from Boss' stomach made them decide it was time to go eat. It wasn't anything too fancy, just some leftovers from the day before. When they were done, they went upstairs and despite it still being early, they went to bed again. Boss may have slept all day but he felt like he could fall asleep at a moment's notice.

"you know, if you still want to have sex tonight, i'm up to it," Sans said as they were getting comfortable on the bed.

Boss took a moment to think about it. "Hmm... I Have Something Else In Mind. Could You..." He averted his eyes and blushed a little. He knew he shouldn't be embarrassed and that Sans wouldn't judge him, but still. "Could You Read Fluffy Bunny?"

"sure boss," Sans said with a smile, not even complaining that he had to get up again to go fetch the book.

Sans began reading and Boss didn't even hear the end of the first page, fast asleep.

**Notes for the Chapter:**

> Sorry it's not a real chapter, but the dice gave me another NO (for Papyrus) and after the day before, I couldn't not link the 2 chapters. I'm sorry for disappointing anyone who wanted to read a sado maso chapter (honestly I really enjoy the kink and was super frustrated the dice gave me a NO for this one...).
> 
> The series of Papyrus' NOs is coming to an end with this chapter, so next one will be a kinky one, I promise.


	13. day 12: Master slave

Master/slave Contract

 

name of the Master: Papyrus  
name of the slave: Sans

implementation date: 10/12/20XX, 20:00  
termination date: 10/13/20XX, 00:00

Both parties acknowledge to have read, understood and agreed to the present document.  
Both parties can end the Scene by using the safeword 'red' or by clicking their fingers twice. Both parties agree to stop immediately if either the Master or the slave uses the safeword and/or -gesture.

 

  * 1\. The slave



The slave agrees to obey any command or rule its Master might give it.  
The slave agrees to accept any punishment its Master might give it if it has failed to obey its Master.  
The slave agrees to acknowledge and strive for no other considerations than its Master's pleasure and well-being.  
The slave agrees to entrust its body, mind and SOUL to its Master for Him/Her/Them to do as He/She/They please/s for the duration of the Scene.

 

  * 2\. The Master



The Master agrees that His/Her/Their slave's mind, body and SOUL are His/Hers/Theirs to do as He/She/They please for the duration of the Scene.  
The Master agrees to care for the slave and arrange for its safety and well-being.  
The Master agrees to decide beforehand of an aftercare period during which He/She/They will tend to His/Her/Their slave's wound/s, physical or mental.  
The Master agrees to respect the slave's boundaries (cf. 3.) if provided with any before the beginning of the Scene.

 

  * 3\. Boundaries



In the case the slave has personal boundaries due to its personal life outside the Scene, kink/sexual/non-kink/non-sexual boundaries may be agreed upon between the slave and the Master. The Master agrees not to do/use/mention any of those boundaries during the Scene.  
The slave's boundary/ies is/are as follow:

  
Any violation of one or more of those rules will immediately render this present contract void.

Signature of the Master:

Signature of the slave:

 

 

* * *

Sans wrote a few words on the piece of paper before signing it and then passed it to Boss who read the addition. 'humiliation play, any kind of magical attack that might damage Hp, any kind of physical pain that might damage Hp, any kind of physical pain that might draw marrow and/or break bone/s'. It was fair, Boss thought as he too signed the contract. Then he stood up and left to kitchen to go to the living room, ordering San- his slave to follow him. He sat down on the couch and crossed his legs.

"Kneel."

His slave did as it was told, getting on the ground before its Master and lowering its eyes.

Boss spoke clearly and authoritatively. "Good. Tonight I Shall Be Your Master And You Shall Be My Slave. You Will Obey My Every Command And Satisfy My Needs. Do You Understand?"

"yes... sir," the slave answered, drawing a displeased grunt from the Master.

"Speak To Me Correctly And With The Respect I Deserve. I Will Not Tolerate Another Slip Up, But Since This Is Your First Mistake, I'll Be Merciful And Let You Try Again. So, Do You Understand?"

The slave hesitated. It didn't seem to understand what it had done wrong until sudden realization hit its face.

"Yes Sir."

Boss smiled. It was so rare to hear Sans speak correctly that he almost wanted to break his role and start laughing but he managed to control himself. Maybe he could even force Sans to pick up his damn sock while he was bound by the contract. He'd have to try that later, for now he had more pressing matters to take care of.

"Now Undress," he commanded and stood up once the slave was naked. He turned around the slave a few times before smacking its hands, sternum and under its chin. "When In The Same Room As Your Master, You Must Stand Correctly. No Slouching Posture Will Be Allowed In My Presence.

"Yes Sir," the slave said as it corrected its posture, bringing its hands behind its back and lifting its head up while still looking down.

Boss went back to sit on the edge of the couch and looked at his slave for a few moments. Stars, Sans was so beautiful...

"Form A Cock."

"Yes Sir," the slave answered as it closed its eyes to focus on their magic, and when it opened them again, a thick ruby cock had manifested between its legs.

It wasn't hard, but that would change soon, Boss thought.

 

 

* * *

The alarm clock on Boss' nightstand let a barely noticeable ring, signaling it was midnight. Sans almost missed it but he saw the time when he turned his head to the left to check if it had been his imagination.

"S-s-Sir Boss... i'Ts Ah! HMMmM... It's mid Night... oooh fu-" He managed to say between Boss' thrusts, who didn't stop nor slow down as he gave a side look to the clock.

"O-OH? AND SO WWWHAT? Hmmm, Fuck! SAns... YOU Want Me TO S-Stop?"

"fuck No"

**Notes for the Chapter:**

> Last year for kinktober, I received an ask for fellcest with Master/slave kink and I didn't know what to do (because it's not a kink I completely understand) so I was kind of dreading this chapter, but I managed to do something! Yay! (sorry anon that it took me a WHOLE FUCKING YEAR)  
> As I was writing, I thought 'why not include a contract?' and after some (quick) research, I found a sample that I took my inspiration from. So the contract in this chapter isn't a real nor complete one by far, though it reflects Papyrus' inexperience at writing one (as my own...).
> 
> (I had fun with Sans' strange speech at the end, but if it's not clear, it's because he's been fucked so well by Papyrus that he doesn't know how to speak anymore: upper or lower case? Same for Papyrus.)


	14. day 13: medical play

Sans shivered. The basement wasn't the warmest place in their home, and the fact that he was naked wasn't helping. He was sitting on the hard and cold shelf, the blueprints pushed to the side, kicking his feet as he waited for Boss to speak.

"Hmm," Boss said pensively as he turned around on his chair.

Sans had to stop his magic from reacting to the sight. Boss was wearing a long lab coat, its creamy white highlighting the pure white of Boss' bones. But what really turned Sans on, and that he didn't get to see often because he knew Boss hated them, was that Boss had his glasses on. Thin and subtle, they sat perfectly on Boss' nasal ridge, his crimson eyelights shining bright and sharp behind them. Such a small change, but Boss was so much more sexy with them. Too bad he never wore them at home.

"There Seems To Be A Problem With Your Magic," Boss said, mimicking the calm and composed tone of a healer. "The Tests Tell Me That Your Pelvis Is The Origin Of The Problem, So I'll Have To Ask You To Lie Back And Open Your Legs."

"yes healer" Sans couldn't help the playful note in his tone.

Boss helped him lie on his back and put a small pillow under his head for support. Then he moved his chair forward and bent down so that his head was at eye's level with Sans' pelvis. He began running his fingers all over the smooth bone, as if to palpate it, and oh stars was it hard for Sans not to just moan. He knew it wouldn't really matter, that it was just part of the play, but he really wanted to know what Boss had in store for him.

"s-so? how is it, healer?" Sans managed to ask between gasps.

"Not So Good," Boss answered, unfazed to Sans' torment. "There Is Something Agitating Your Magic And I Don't Know What."

_oh you know perfectly what._

"Could You Try Summoning Your Magic to See How It Reacts, Please?"

Sans didn't need to be asked twice and formed an already wet pussy for Boss to 'play' with. Boss ran his fingers down the lips, opening them to reveal the throbbing hole. He couldn't help a hiss that made Sans shiver and whimper in need.

"There Is-" Boss' voice got caught in his throat and he coughed. "There Is A Way To Determine What's Causing The Problem. It's A Quite Simple Method, Really."

"what is the method, healer?" Sans squirmed under Boss' touch. He just wanted Boss to fuck him, was it too much to ask?

"We Just Need To Know If Your Magic Tastes Sweet Or Salty. Then I Will Know What Medication To Give You," he explained and honestly Sans didn't even cared if it made sense or not. It probably didn't.

"and how are you going to know that, healer?"

"We Could Do More Tests..." Boss began as he straightened up, drawing away from Sans' pussy, making him whine at the loss of his fingers. "But There Is A Quicker Method... It's Still Experimental, But..." He trailed off.

"healer, i'm... in a bit of a hurry," Sans whispered as he locked gaze with Boss. "what is this quicker method you're speaking about, please tell me?"

"Well..." Boss began as he stood up from the chair to loom over Sans, his eyes shining with lust. "I Could Just Taste Your Magic Myself, And So We'll Know Right Away What We Need To Do."

"like i said, i'm in a hurry," Sans barely had the time to say before Boss pulled him by the legs and he was nasal ridge deep into Sans' pussy, sucking and licking the wet and hot magic. "oh, h-healer..." Sans moaned as he was thoroughly tongue-fucked.

After several minutes of Boss' head trapped between Sans' legs, he finally let go of the magic, a thin trail of saliva still connecting them.

"s-so?" Sans shakingly asked.

"I'm Not Sure, Maybe You Could Help Me Out," Boss replied as he bent over Sans' shivering form, putting his arms on either sides of Sans' head. "Stick Your Tongue Out, Please."

Sans let his tongue loll out of his mouth for Boss to press his own crimson one, feeling, tasting his juices on the long appendage. He couldn't help a moan from escaping him as he wrapped his arms around Boss' neck to pull him closer.

"Do You Feel How Sweet Your Magic Is?" Boss grunted more than he asked, pausing from his licking.

"yes... and it's... it's still agitated, healer..."

"That Won't Do..." Boss chuckled with a devilish grin. "You Need To Let Go Of Your Infected Magic. I Can Help With That If You Want, By Inserting A Particular Tool In The Infected Zone," he continued as he began unbuckling his belt.

"y-yeah..." Sans moaned again, not really sure if he had been asked a question.

"Then Hold Your Legs Up For Me," Boss said as he opened the zipper of his pants to reveal his erection and Sans whined at the sight. "Don't Be Intimidated By The Size, It Won't Hurt."

"oh i hope it does," Sans managed to say before his treatment began.

**Notes for the Chapter:**

> Not my kink at all, so I hope the chapter is okay.  
> Btw, the funniest part in this fic (beside writing kinky fellcest of course) is to find ways to adapt the kinks to the Undertale Universe. So I figured that monsters, being made of magic, would have healers rather than doctors. I originally had Sans call Papyrus 'doctor' but then I changed it.


	15. day 14: sensory deprivation

Everything was dark and silent. Sans couldn't move. The gag in his mouth prevented him from saying anything and the scarf that had been tied over both his mouth and his nose smelled like Boss, overpowering any other smell. So Sans was completely helpless.

But he wasn't scared.

There was one thing that hadn't left him since they had started the evening with Boss an hour ago. It was Boss' touch. Whether it was just a brush of his fingers, or his whole body pressed against Sans, Boss hadn't stopped touching him for even one second. Sans never really knew where he was, but he knew he was always there.

And by there, he meant between his legs. Sans was being tongue-fucked or finger-fucked, he didn't even know, but either way it felt so fucking good. There was something in not being able to see Boss that turned him on to no end. His imagination provided with the visuals, and while it was trickier to make up the sounds in his mind, he could still hear his breath and his moans in his head. If he focused enough, he was sure he could hear the wet sounds that Boss' tongue, he guessed, made as it slipped in and out of Sans' pussy.

His body was on fire, every part that Boss was touching felt like it was melting. Sans didn't want to accidently hit Boss by flailing around, but he had a hard time keeping still. And honestly, the less he moved, the more he felt those long fingers move inside him and that made him crazy with lust.

He let out a muffled squeak when he felt Boss' big hand land on his sternum to caress it, until Boss changed his mind and began running his fingers, or rather claws given how pointy they were (did Boss file his bones??), all over the bone, leaving scratches accross the ribs. Sans tried to arch his back to show Boss how much he liked it, to make him understand he wanted more, but either Boss didn't get the message or he simply didn't care and continued to tease Sans.

It was torture not to be able to curse, Sans realized as he could only whine and grumble behind the gag. He could almost hear Boss chuckle, even with the noise-canceling headphones on. He jerked his tied together arms. But nothing changed. He was completely helpless. And utterly aroused.

Instead of what he couldn't do, he tried focusing on what he could feel, even if it was hard with Boss' finger-ish tongue still buried inside him. He could feel something hot lightly hit his face from time to time, something he hadn't noticed previously. It was tapping his forehead repeatedly, and Sans could only tell it was soft and wet... and long...

He let out a loud whine and wriggled again under Boss, who he only now realized was in fact upside down. They were in a fucking 69! And Sans hadn't even noticed! Boss removed his tongue-ish fingers from Sans' pussy and finally moved over him. He must've understood Sans had finally got it, and after the bed dipped here and there a few times, Sans felt a hot breath on his collar bone and tilted his head up, moaning when Boss began sucking the bone.

Sans spread his legs open in an invitation and inwardly smiled when he felt the tip of Boss' erection touch the inner folds of his pussy. But Boss didn't push inside yet. Sans' protests died in his head when Boss' cock slid up and down Sans' pussy, brushing the clit and making Sans dizzy.

After a few more minutes of torture, Boss finally, fucking finally pushed himself inside, his long cock impaling Sans who wailed in pleasure at finally being filled. And it seemed Boss was as relieved as Sans was, because he didn't lose time in thrusting in and out at a rapid pace, rocking Sans' small body underneath him. Sans was pounded relentlessly into the mattress, and all he could do was moan and whimper behind the gag, so he went all out. He was sure he was screaming by now and that his throat would be sore in the morning, but he didn't care one bit. All he wanted was that cock, and now that it was inside him, he would keep it in for as long as he could.

Unable to do more that move his head, he began nodding frantically, hoping that Boss would see it and interpret it as his permission to go faster. His prayers were heard but not answered like he thought. Boss instead lowered a hand to play with his clit, making Sans see stars behind his closed sockets and yell even more. Somehow, the fact that he couldn't hear made him want to scream even louder.

Sans felt his climax approach quickly and kicked his legs in the mattress. He knew Boss knew he loved to have his legs on Boss' shoulders when cumming, and was more than happy when he felt one strong bony hand grab his ankles and lift them until he was almost not touching the mattress. In this position, he couldn't move at all, his arms bound above his head to the headboard and his legs in Boss' iron grip.

After a few more powerful thrusts, he felt himself tip over the edge, his pussy tightening around Boss' cock, who didn't slow down his pace at all, making Sans whimper loudly. After all the torture from before, his clit was extremely sensitive, and the friction from Boss' cock was almost enough to make him cum once more. He let out a long relieved sigh when he felt Boss finally slow down, only to suddenly feel him blow his load inside Sans' pussy, making him cum again after all.

It was a strange feeling, really, to be able to litterally feel Boss' hot cum inside his pussy. He usually didn't even feel it but with his sense of touch highlighted by the loss of the other senses, he could feel just about anything. As Sans caught his breath, Boss began to untie his hands and then took care of the blindfold and the gag, until Sans opened his eyes to Boss looming over him, with his... his cock in his hand? But Sans could still feel it in his...

Sans propped himself up on his elbows to see what was going on down there and saw a big plastic dildo buried in his pussy, its artificial juices dripping from the entrance.

"what the-" he began, only to shoot a displeased glare at Boss, who smiled smugly.

"What? You're Not Going To Tell Me You Didn't Enjoy Yourself?" He asked in that really irritating tone he loved to use.

"hmpf. i would've prefered if you just made me suck you," he grumbled under his breath, turning his head to the side with a pout.

"Oh, I'm Sure We Can Figure Out Something," Boss teased as he grabbed his hard cock and pressed it to Sans' mouth.

**Notes for the Chapter:**

> A big big kink of mine but so hard to write!!! T0T


End file.
